U.S. patent number 7,577,441 [Application Number 11/769,405] was granted by the patent office on 2009-08-18 for method and device for determining a position of a portable electronic device.
This patent grant is currently assigned to Motorola, Inc.. Invention is credited to Yoko Nonoyama.
United States Patent |
7,577,441 |
Nonoyama |
August 18, 2009 |
Method and device for determining a position of a portable
electronic device
Abstract
A method for determining a position of a portable electronic
device is useful for conserving power, processor and bandwidth
resources. The method includes detecting at a portable electronic
device a first signal received from a local terminal (step 605). In
response to the first signal, a second signal is transmitted from
the device, indicating a proximity of the portable electronic
device to the local terminal (step 610). Positioning method
priority information, which is based on a location of the local
terminal and is received from the local terminal in response to the
second signal, is then processed at the device (step 615). A
positioning method priority list based on the positioning method
priority information is then processed (step 620). Finally, the
position of the portable electronic device is determined using a
positioning method identified in the positioning method priority
list (step 625).
Inventors: |
Nonoyama; Yoko (Tokyo,
JP) |
Assignee: |
Motorola, Inc. (Schaumburg,
IL)
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Family
ID: |
40159756 |
Appl.
No.: |
11/769,405 |
Filed: |
June 27, 2007 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20090002237 A1 |
Jan 1, 2009 |
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Current U.S.
Class: |
455/456.1 |
Current CPC
Class: |
H04W
64/00 (20130101); G01S 5/02 (20130101); G01S
5/0263 (20130101); Y02D 30/70 (20200801); Y02D
70/142 (20180101); Y02D 70/164 (20180101); Y02D
70/1224 (20180101); Y02D 70/166 (20180101); H04W
88/06 (20130101); Y02D 70/144 (20180101) |
Current International
Class: |
H04W
24/00 (20060101) |
Field of
Search: |
;455/456.1,456.2
;340/572.4,686.6 ;342/450,457,463-465,357.14 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1418439 |
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Dec 2004 |
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EP |
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03107708 |
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Dec 2003 |
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WO |
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Primary Examiner: Tarcza; Thomas H
Assistant Examiner: Mull; Fred H
Claims
I claim:
1. A method for determining a position of a portable electronic
device, the method comprising: detecting a first signal received
from a local terminal; transmitting from the portable electronic
device, in response to the first signal, a second signal indicating
a proximity of the portable electronic device to the local
terminal; processing positioning method priority information, which
identifies a ranked list of a plurality of positioning methods, is
based on a location of the local terminal and is received from the
local terminal in response to the second signal; updating a
positioning method priority list based on the positioning method
priority information; and determining the position of the portable
electronic device using a positioning method identified in the
positioning method priority list.
2. The method of claim 1, wherein the second signal is transmitted
from a radio frequency identification tag.
3. The method of claim 1, wherein the first and second signals are
near field communications.
4. The method of claim 1, wherein the positioning method priority
list is updated before executing any positioning method identified
in the positioning method priority list.
5. The method of claim 1, further comprising changing the
positioning method priority list to a default priority list after
the expiration of a predetermined time period.
6. The method of claim 1, wherein the positioning method priority
information comprises a current position of the portable electronic
device.
7. The method of claim 1, wherein processing the positioning method
priority information comprises reading the positioning method
priority information from a radio frequency identification tag in
the portable electronic device.
8. The method of claim 1, wherein the positioning method priority
list identifies positioning methods selected from the following
methods: satellite based, cell based, short range wireless based,
radio frequency identification based, and hybrid positioning
methods.
9. The method of claim 1, wherein the positioning method priority
information identifies a single preferred positioning method.
10. A portable electronic device comprising: a computer readable
medium comprising: computer readable program code components
configured to cause detecting a first signal received from a local
terminal; computer readable program code components configured to
cause transmitting from the portable electronic device, in response
to the first signal, a second signal indicating a proximity of the
portable electronic device to the local terminal; computer readable
program code components configured to cause processing positioning
method priority information, which identifies a ranked list of a
plurality of positioning methods, is based on a location of the
local terminal and is received from the local terminal in response
to the second signal; computer readable program code components
configured to cause updating a positioning method priority list
based on the positioning method priority information; and computer
readable program code components configured to cause determining
the position of the portable electronic device using a positioning
method identified in the positioning method priority list.
11. The device of claim 10, wherein the first and second signals
are near field communications.
12. The device of claim 10, wherein the positioning method priority
list is updated before executing any positioning method identified
in the positioning method priority list.
13. The device of claim 10, further comprising computer readable
program code components configured to cause changing the
positioning method priority list to a default priority list after
the expiration of a predetermined time period.
14. The device of claim 10, wherein the positioning method priority
information comprises a current position of the portable electronic
device.
15. The device of claim 10, wherein processing the positioning
method priority information comprises reading the positioning
method priority information from a radio frequency identification
tag in the portable electronic device.
16. A method for determining a position of a portable electronic
device, the method comprising: detecting a first signal received
from a local terminal; transmitting from the portable electronic
device, in response to the first signal, a second signal indicating
a proximity of the portable electronic device to the local
terminal; processing positioning method priority information, which
is based on a location of the local terminal and is received from
the local terminal in response to the second signal; updating a
positioning method priority list based on the positioning method
priority information, wherein the positioning method priority list
is updated before executing any positioning method identified in
the positioning method priority list; and determining the position
of the portable electronic device using a positioning method
identified in the positioning method priority list.
17. A method for determining a position of a portable electronic
device, the method comprising: detecting a first signal received
from a local terminal; transmitting from the portable electronic
device, in response to the first signal, a second signal indicating
a proximity of the portable electronic device to the local
terminal; processing positioning method priority information, which
is based on a location of the local terminal and is received from
the local terminal in response to the second signal; updating a
positioning method priority list based on the positioning method
priority information; determining the position of the portable
electronic device using a positioning method identified in the
positioning method priority list; and changing the positioning
method priority list to a default priority list after the
expiration of a predetermined time period.
18. A method for determining a position of a portable electronic
device, the method comprising: detecting a first signal received
from a local terminal; transmitting from the portable electronic
device, in response to the first signal, a second signal indicating
a proximity of the portable electronic device to the local
terminal, wherein transmitting the second signal is performed using
power from a wireless excitation signal received from the local
terminal; processing positioning method priority information, which
is based on a location of the local terminal and is received from
the local terminal in response to the second signal; updating a
positioning method priority list based on the positioning method
priority information; and determining the position of the portable
electronic device using a positioning method identified in the
positioning method priority list.
19. A method for determining a position of a portable electronic
device, the method comprising: detecting a first signal received
from a local terminal; transmitting from the portable electronic
device, in response to the first signal, a second signal indicating
a proximity of the portable electronic device to the local
terminal; processing positioning method priority information, which
is based on a location of the local terminal and is received from
the local terminal in response to the second signal; updating a
positioning method priority list based on the positioning method
priority information; and determining the position of the portable
electronic device using a positioning method identified in the
positioning method priority list; wherein the method conforms to
the Open Mobile Alliance Secure User Plane Location 2.0 Periodic
Trigger standard.
20. A portable electronic device comprising: a computer readable
medium comprising: computer readable program code components
configured to cause detecting a first signal received from a local
terminal; computer readable program code components configured to
cause transmitting from the portable electronic device, in response
to the first signal, a second signal indicating a proximity of the
portable electronic device to the local terminal, wherein the
second signal is transmitted from a radio frequency identification
tag; computer readable program code components configured to cause
processing positioning method priority information, which is based
on a location of the local terminal and is received from the local
terminal in response to the second signal; computer readable
program code components configured to cause updating a positioning
method priority list based on the positioning method priority
information; and computer readable program code components
configured to cause determining the position of the portable
electronic device using a positioning method identified in the
positioning method priority list.
Description
FIELD OF THE INVENTION
The present invention relates generally to portable electronic
devices, and in particular to determining a position of a portable
electronic device using a positioning method selected from a
positioning method priority list.
BACKGROUND
Mobile telephones and other portable electronic devices
increasingly include a locating feature that enables a current
geographic location of the devices to be either displayed on the
devices or transmitted to a remote receiver. These features are
generally called location services (abbreviated as LCS, for
"LoCation Services"). LCS features that display location
coordinates on a device are useful, for example, to device users
who need to know where they are located relative to geographic map
coordinates. Thus LCS features can enable a device user to initiate
a location request where the device acts as a Global Positioning
System (GPS) terminal. Also, location requests may be initiated by
third parties and transmitted to a device over a wireless network.
Such third party requests are useful in various circumstances. For
example, mobile telephone networks may be able to improve network
efficiency and provide better Quality of Service (QoS) and roaming
rates to a mobile user if the network can periodically monitor a
mobile telephone location. Also, emergency services can sometimes
save lives by rapidly and accurately identifying where emergency
phone calls have originated. Other useful location-based services
and data that can be provided through portable electronic devices
include maps, weather forecasts, traffic data, and local news.
Various locating technologies can be used to determine the location
of a portable electronic device. For example, the Global
Positioning System (GPS) can be used to identify a location
anywhere in the world of some mobile telephones. However, because
most mobile telephones are already operatively connected to
land-based network stations, and do not need to communicate solely
with satellites, Assisted GPS (A-GPS) services are commonly used to
incorporate better and more efficient location services into mobile
telephones. Secure User Plane Location (SUPL) is a technology
developed by the Open Mobile Alliance (OMA) that concerns the
transfer of assistance data and positioning data between a portable
electronic device and a location platform, and includes standards
such as the Open Mobile Alliance Secure User Plane Location 2.0
Periodic Trigger standard. A "user plane" means that assistance
data and positioning data are transmitted between the device and
the location platform over a conventional wireless communication
channel such as a General Packet Radio Service (GPRS) channel. User
plane communications are thus distinguished from control plane
communications where assistance data and positioning data are
transmitted between a device and a location platform over a
separate signaling channel in a network. Before a portable
electronic device can utilize the location services of a location
platform, the device and the location platform generally are
mutually authenticated. Such mutual authentication can include
obtaining authentication data, such as shared keys, from a
particular domain. For example, a particular domain associated with
a location platform can be identified using a Fully Qualified
Domain Name (FQDN), such as an internet protocol (IP) version 4
address, that is included in a universal integrated circuit card
(UICC) that is operatively coupled to the device. The device can
use the FQDN to contact the location platform and complete mutual
authentication.
Other locating technologies include short-range wireless based
locating technologies that measure parameters of a wireless local
area network (WLAN), such as a received signal strength indicator
(RSSI) or a time difference of arrival (TDOA) parameter. Still
other locating technologies include other hybrid approaches that
employ a combination of satellite based, cell based, and
short-range wireless based locating technologies.
The various above described locating technologies and LCS
applications can consume a significant amount of power and
processing resources of a portable electronic device such as a
mobile telephone. Acquiring location information such as geographic
coordinates, and performing ancillary processes such as mutual
authentication, consumes device battery power and employs processor
resources that may cause other processor intensive applications of
a device to be slowed down. Further, frequent transmission of such
messages contributes to network congestion and can reduce network
bandwidth for all network users.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be readily understood and put into
practical effect, reference will now be made to exemplary
embodiments as illustrated with reference to the accompanying
figures, wherein like reference numbers refer to identical or
functionally similar elements throughout the separate views. The
figures together with a detailed description below, are
incorporated in and form part of the specification, and serve to
further illustrate the embodiments and explain various principles
and advantages, in accordance with the present invention,
where:
FIG. 1 is a schematic diagram illustrating a portable electronic
device in the form of a mobile telephone, according to some
embodiments of the present invention.
FIG. 2 is a diagram illustrating a network in which a mobile
telephone interacts with a variety of locating technology systems,
according to some embodiments of the present invention.
FIG. 3 is a flow diagram illustrating a method of updating a
positioning method priority list (PMPL) based on positioning method
priority information received from a radio frequency identification
(RFID) tag in a mobile telephone, according to some embodiments of
the present invention.
FIG. 4 is a flow diagram illustrating a method for iteratively
determining whether any positioning method identified in a
positioning method priority list satisfies quality of position
(QOP) parameters identified in a positioning request for location
services (LCS), according to some embodiments of the present
invention.
FIG. 5 is a message sequence chart illustrating a method of
updating a positioning method priority list (PMPL) in response to
movement of a mobile telephone through a subway system, according
to some embodiments of the present invention.
FIG. 6 is a general flow diagram illustrating a method for
determining a position of a portable electronic device, according
to some embodiments of the present invention.
Skilled artisans will appreciate that elements in the figures are
illustrated for simplicity and clarity and have not necessarily
been drawn to scale. For example, the dimensions of some of the
elements in the figures may be exaggerated relative to other
elements to help to improve understanding of embodiments of the
present invention.
DETAILED DESCRIPTION
Before describing in detail embodiments that are in accordance with
the present invention, it should be observed that the embodiments
reside primarily in combinations of method steps and apparatus
components related to determining a position of a portable
electronic device. Accordingly, the apparatus components and method
steps have been represented where appropriate by conventional
symbols in the drawings, showing only those specific details that
are pertinent to understanding the embodiments of the present
invention so as not to obscure the disclosure with details that
will be readily apparent to those of ordinary skill in the art
having the benefit of the description herein.
In this document, relational terms such as first and second, top
and bottom, and the like may be used solely to distinguish one
entity or action from another entity or action without necessarily
requiring or implying any actual such relationship or order between
such entities or actions. The terms "comprises," "comprising," or
any other variation thereof, are intended to cover a non-exclusive
inclusion, such that a process, method, article, or apparatus that
comprises a list of elements does not include only those elements
but may include other elements not expressly listed or inherent to
such process, method, article, or apparatus. An element preceded by
"comprises a . . . " does not, without more constraints, preclude
the existence of additional identical elements in the process,
method, article, or apparatus that comprises the element.
According to one aspect, the present invention is a method for
determining a position of a portable electronic device. The method
includes detecting at a portable electronic device a first signal
received from a local terminal. In response to the first signal, a
second signal is transmitted from the device, indicating a
proximity of the portable electronic device to the local terminal.
Positioning method priority information, which is based on a
location of the local terminal and is received from the local
terminal in response to the second signal, is then processed at the
device. A positioning method priority list based on the positioning
method priority information is then processed. Finally, the
position of the portable electronic device is determined using a
positioning method identified in the positioning method priority
list.
Some embodiments of the present invention therefore enable a
portable electronic device to prioritize available positioning
methods based on current circumstances or locations of the device,
but without requiring the device to actually execute any of the
positioning methods identified in a positioning method priority
list. Then only one or more positioning methods, which are assigned
a high priority level in the positioning method priority list, are
executed in order to determine the position of the device. That can
significantly conserve battery power and processor resources of the
device, because positioning methods assigned a lower priority do
not need to be executed and tested in order to determine that they
should be assigned a low priority. Rather, the positioning method
priority information is received directly from a local terminal,
such as a radio frequency identification (RFID) card read/write
terminal, that is in proximity to the portable electronic
device.
Referring to FIG. 1, a schematic diagram illustrates a portable
electronic device in the form of a mobile telephone 100, according
to some embodiments of the present invention. The mobile telephone
100 comprises a radio frequency communications unit 102 coupled to
be in communication with a common data and address bus 117 of a
processor 103. The mobile telephone 100 also has a keypad 106, and
a display screen 105, such as a touch screen coupled to be in
communication with the processor 103.
The processor 103 also includes an encoder/decoder 111 with an
associated code Read Only Memory (ROM) 112 for storing data for
encoding and decoding voice or other signals that may be
transmitted or received by the mobile telephone 100. The processor
103 further includes a microprocessor 113 coupled, by the common
data and address bus 117, to the encoder/decoder 111, a character
Read Only Memory (ROM) 114, a Random Access Memory (RAM) 104,
programmable memory 116 and a Subscriber Identity Module (SIM)
interface 118. The programmable memory 116 and a SIM operatively
coupled to the SIM interface 118 each can store, among other
things, selected text messages and a telephone number database
comprising a number field for telephone numbers and a name field
for identifiers associated with one of the numbers in the name
field.
The radio frequency communications unit 102 is a combined receiver
and transmitter having a common antenna 107. The communications
unit 102 has a cell transceiver 108 coupled to the antenna 107 via
a radio frequency amplifier 109. The cell transceiver 108 is also
coupled to a combined modulator/demodulator 110 that is coupled to
the encoder/decoder 111. For example, the cell transceiver 108 can
be adapted for use with wideband code division multiple access
(WCDMA), global system for mobile (GSM), or general packet radio
service (GPRS) cell based communications. Other transceivers (not
shown) also can be included in the radio frequency communications
unit 102 for use with other radio communication systems such as the
global positioning system (GPS), Bluetooth.TM. systems, and
wireless local area network (WLAN) systems.
The microprocessor 113 has ports for coupling to the keypad 106 and
to the display screen 105. The microprocessor 113 further has ports
for coupling to an alert module 115 that typically contains an
alert speaker, vibrator motor and associated drivers; to a radio
frequency identification (RFID) tag 119; to a microphone 120; and
to a communications speaker 122. The character ROM 114 stores code
for decoding or encoding data such as text messages that may be
received by the communications unit 102. In some embodiments of the
present invention, the character ROM 114, the programmable memory
116, or a SIM also can store operating code (OC) for the
microprocessor 113 and code for performing functions associated
with the mobile telephone 100. For example, the programmable memory
116 can comprise location services computer readable program code
components 125 configured to cause execution of a method for
determining a position of the mobile telephone 100, according to
some embodiments of the present invention.
Referring to FIG. 2, a diagram illustrates a network 200 in which
the mobile telephone 100 interacts with a variety of locating
technology systems, according to some embodiments of the present
invention. For example, the location services program code
components 125 can define a positioning service provider (PSP)
module 205 that interacts with the cell transceiver 108, a GPS
transceiver 210, a Bluetooth.TM. transceiver 215, and a WLAN
transceiver 220. The GPS transceiver 210 can wirelessly connect to
a GPS satellite 225, the Bluetooth.TM. transceiver 215 can
wirelessly connect to other Bluetooth.TM. devices such as a GPS
device 230 in a car navigation system, or a base transceiver (BT)
at an access point (AP) 235. The cell transceiver 108 can
wirelessly connect to a network cell 240, and the WLAN transceiver
220 can wirelessly connect to a WLAN AP 245. The AP 235, network
cell 240 and WLAN AP 245 can in turn operatively connect to a core
network 250, such as the Internet, and obtain location information
and services from for example, a location service provider 251, a
public transport centralized server 252 and a map server 253.
According to some prior art techniques, determining which available
positioning method at the mobile telephone 100 is best in a given
circumstance or location would require employing each of the GPS
transceiver 210, the Bluetooth.TM. transceiver 215, the cell
transceiver 108, and the WLAN transceiver 220, to iteratively
execute each of their respective positioning methods. The results
then would be compared and prioritized. However, such testing and
comparison of multiple available positioning methods wastes power,
time, processor, and network resources.
According to some embodiments of the present invention, a local
terminal such as an RFID reader/writer 255 provides positioning
method priority information directly to the mobile telephone 100.
Therefore the mobile telephone 100 can determine immediately which
positioning method is appropriate in a given circumstance or
location without executing any positioning method identified in a
positioning method priority list.
For example, the RFID reader/writer 255 can be positioned in a
vehicle equipped with the GPS device 230. Thus it may be
appropriate that, when the mobile telephone 100 is located in the
vehicle, location services of the mobile telephone 100 should
always first use the GPS device 230 accessed through the
Bluetooth.TM. transceiver 215. Therefore, the Bluetooth.TM.
transceiver 215 should be at the top of a positioning method
priority list whenever the mobile telephone 100 is in the vehicle.
That can be accomplished by having the RFID reader/writer 255
transmit positioning method priority information directly to the
RFID tag 119 in the mobile telephone 100. A positioning method
selector (PMS) module 260 can then read the positioning method
priority information from the RFID tag 119 and update a positioning
method priority list (PMPL) 265. For example, the PMPL 265 can
prioritise various positioning methods such as satellite based,
cell based, short range wireless based, radio frequency
identification based, and hybrid positioning methods. The
positioning service provider (PSP) module 205 can then obtain a
preferred positioning method from the PMS module 260 and activate
an appropriate transceiver such as one of the transceivers 108,
210, 215, or 220.
According to another example, the RFID reader/writer 255 can be
associated with an electronic lock to a building, such as a home or
office. The RFID tag 119 in the mobile telephone 100 then can
function as an electronic key. Thus each time a user of the mobile
telephone 100 enters or leaves the building, the RFID tag 119
communicates with the RFID reader/writer 255. While the user is
inside the building, a preferred location technology may be
accessed through the WLAN network 245 using the WLAN transceiver
220. Therefore, each time the user enters the building the RFID
reader/writer 225 transmits positioning method priority information
to the RFID tag 119 that identifies use of the WLAN transceiver 220
as the most preferred positioning method.
Still other examples include placing the RFID reader/writer 255 in
public locations such as bus stations, train stations, concert
halls, shopping centers, and various public buildings. The RFID
reader/writer 255 then can be programmed to identify a single
preferred positioning method, or a ranked list of a plurality of
positioning methods, appropriate for that particular public
location. Each time a user of a portable electronic device such as
the mobile telephone 100 is in close proximity, the RFID
reader/writer 255 transmits the appropriate positioning method
priority information to the electronic device, such as to the RFID
tag 119.
Those skilled in the art will appreciate that other means of
communicating between a portable electronic device and a local
terminal are also enabled by the present invention. For example,
rather than employing the RFID tag 119 and the RFID reader/writer
255, other localized communication methods can be employed such as
Near Field Communications, felicity card (FeliCa) communications,
or Mifare communications.
According to some embodiments of the present invention, the
positioning method priority list can be changed to a default
priority list after the expiration of a predetermined time period.
For example, the location services program code components 125 can
further define a default priority list (DPL) 270 that defines a
positioning method priority list for use when no other suitable
priority list is identified. For example, the positioning method
selector (PMS) 260 can set a timer when the positioning method
priority list (PMPL) 265 is changed. If a further update to the
PMPL 265 is not processed before expiration of the timer, then the
PMPL 265 is reset to the DPL 270. A positioning method database
(PMDB) 275 can be used to store effective time periods and other
attributes associated with various positioning methods.
A location application module 280 can be used to process requests
for location services (LCS) from various sources. For example, such
requests can include mobile terminated location requests (MTLRs),
network initiated location requests (NILRs), or mobile originated
location requests (MOLRs). MTLRs are location requests that are
initiated by another network user, such as other mobile stations,
websites or information services. NILRs are location requests that
are received from a mobile network where the network is not
requesting verification or notification. Typically, NILRs are used
for locating mobile stations for emergency or law-enforcement
purposes. MOLRs are location requests that originate from the
mobile telephone 100 itself, such as when a user of the mobile
telephone 100 requests his or her location.
Referring to FIG. 3, a flow diagram illustrates a method 300 of
updating the positioning method priority list (PMPL) 265 based on
positioning method priority information received from the RFID tag
119, according to some embodiments of the present invention. Before
the method 300 begins, when the mobile telephone 100 is first
powered on, the PSP 205 copies data from the DPL 270 to the PMPL
265. Then, at step 305, it is determined whether new data has been
written on the RFID tag 119. If so, at step 310, the PMS 260 reads
an attribute from the new data. At step 315, it is determined
whether the attribute is already stored in the PMDB 275.
At step 320, if the attribute is not already stored in the PMDB
275, then a search for a priority list associated with the
attribute is performed. For example, databases provided on the
Internet by LCS providers, or by owners of the RFID reader/writer
255, such as rail station companies or facility management
companies, can be searched to obtain a priority list. Then at step
325 it is determined whether a priority list was found. If not, at
step 330 a TMP_PRIORITY field is assigned a null value; if so, at
step 335 the TMP_PRIORITY field is assigned the value of the found
priority list. Next, at step 340, it is determined whether the PMDB
275 is full. If so, at step 345 a least recently or least
frequently used attribute entry is deleted from the PMDB 275; if
not, at step 350 the found attribute associated with the
TMP_PRIORITY field is saved in the PMDB 275.
At step 355, the priority list associated with the found attribute
is retrieved. Next, at step 360 it is determined whether the
priority list is empty. If so, at step 365 the TMP_PRIORITY field
is assigned a value corresponding to the DPL 270; if not, at step
370 the TMP_PRIORITY field is assigned a value corresponding to the
found priority list associated with the attribute. Finally, at step
375, the PMPL 265 is defined as the priority list identified by the
TMP_PRIORITY field.
An effective time for each attribute also can be specified and
stored in the PMDB 275 so that a selected priority list will expire
after the effective time. The PMPL 265 then will be overwritten
with the DPL 270. That prevents the PMPL 265 from maintaining an
out of date, context-specific priority list.
Referring to FIG. 4, a flow diagram illustrates a method 400 for
iteratively determining whether any positioning method identified
in a positioning method priority list satisfies quality of position
(QOP) parameters identified in a positioning request for location
services (LCS), according to some embodiments of the present
invention. At step 405, when the mobile telephone 100 is first
powered on the data from the DPL 270 is copied to the PMPL 265. At
step 410 it is then determined whether a positioning request has
been received. If so, a variable N is set to a value of one. At
step 420, the PSP 205 initiates a positioning method that
corresponds to the first priority method in the PMPL 265. At step
425 it is determined whether the first priority method succeeded in
providing a positioning fix that satisfied the required QOP
parameters. If not, then at step 430 it is determined whether N is
less than a maximum number of positioning methods available to the
mobile telephone 100. If so, at step 435 the value of N is
incremented by one and the method 400 returns to step 420; if not,
then a "positioning failed" message is reported to the LCS
requestor. At step 445, if one of the available positioning methods
succeeds, then the associated positioning result is reported to the
LCS requestor.
Referring to FIG. 5, a message sequence chart illustrates a method
500 of updating the positioning method priority list (PMPL) 265 in
response to movement of the mobile telephone 100 through a subway
system, according to some embodiments of the present invention. As
shown in block 505, consider that the PMPL 265 initially
prioritizes three available positioning methods, where use of the
GPS transceiver 210 is assigned a first priority, use of the cell
transceiver 108 is assigned a second priority, and use of the WLAN
transceiver 220 is assigned a tertiary priority. Also consider that
the mobile telephone 100 can function as a target SUPL enabled
terminal (SET) that is in communication, such as through the
network 250, with a home SUPL location platform (H-SLP) 510.
Further, consider that the H-SLP 510 is in communication, such as
through the network 250, with a SUPL agent 515. A mobile location
protocol triggered location reporting request (MLP TLRR) 520 is
transmitted from the SUPL agent 515 to the H-SLP 510, and indicates
that a current location of the mobile telephone 100 has been
requested. The H-SLP 510 therefore looks up routing information for
the mobile telephone 100 in a routing table 525 and transmits a
SUPL initiation (INIT) message 530 to the mobile telephone 100. The
mobile telephone 100 then responds with a SUPL TRIGGERED START
message 535 that identifies SET capabilities including the
positioning methods identified in the PMPL 265. The mobile
telephone 100 then receives a SUPL TRIGGERED RESPONSE message 540,
which indicates preferred positioning methods of the H-SLP 510, and
sets a timer T. The H-SLP 510 then transmits a mobile location
protocol triggered location reporting answer (MLP TLRA) 545 to the
SUPL agent 515. After expiration of the timer T, the PSP 205 copies
the PMPL 265 to a posmethods-avail field in a SUPL positioning
initiation (POS INIT) message 550 that is transmitted to the H-SLP
510. A first SUPL positioning session 555 is then started using the
GPS transceiver 210, and another timer T is started. A MTP TLRA 560
including results of the first SUPL positioning session 555 is then
transmitted from the H-SLP 510 to the SUPL agent 515.
At point 565, consider that a user of the mobile telephone 100
enters a subway using a ticket gate at a subway station A that
includes an RFID reader/writer 255. By employing the method 300
described above, the PMPL 265 is updated. Block 570 illustrates the
updated PMPL 265, where the three available positioning methods are
reprioritized so that use of the WLAN transceiver 220 is assigned a
first priority, use of the cell transceiver 108 is assigned a
second priority, and use of the GPS transceiver 210 is assigned a
tertiary priority. When the timer T again expires, the mobile
telephone 100 transmits a SUPL POS INIT message 575 to the H-SLP
510. A second SUPL positioning session 580 is then started using
the WLAN transceiver 220, and another timer T is started. A MTP
TLRA 585 including results of the second SUPL positioning session
580 is then transmitted from the H-SLP 510 to the SUPL agent
515.
At point 587, consider that a user of the mobile telephone 100
leaves the subway using a ticket gate at a subway station B that
includes another RFID reader/writer 255. By employing the method
300 described above, the PMPL 265 is again updated. Block 590
illustrates the updated PMPL 265, where the three available
positioning methods are reprioritized so that use of the GPS
transceiver 210 is assigned a first priority, use of the cell
transceiver 108 is assigned a second priority, and use of the WLAN
transceiver 220 is assigned a tertiary priority. When the timer T
again expires, the mobile telephone 100 transmits a SUPL POS INIT
message 592 to the H-SLP 510. A third SUPL positioning session 595
is then started using the GPS transceiver 210. A MTP TLRA 597
including results of the third SUPL positioning session 595 is then
transmitted from the H-SLP 510 to the SUPL agent 515.
Therefore, according to the method 500, the PMPL 265 is
automatically updated to identify the WLAN transceiver 220 as a
source of a preferred positioning method while a user of the mobile
telephone 100 is within the subway. But each of the available
positioning methods that use the transceivers 108, 210, 215, and
220 do not need to be tested in order to determine that the WLAN
transceiver 220 is preferred, thus conserving battery power and
processor resources in the mobile telephone 100, and bandwidth
resources in both the network 200 and the network 250.
Referring to FIG. 6, a general flow diagram illustrates a method
600 for determining a position of a portable electronic device,
according to some embodiments of the present invention. At step
605, a first signal received from a local terminal is detected. For
example, the RFID tag 119 detects a signal from the RFID
reader/writer 255.
At step 610, a second signal indicating a proximity of the portable
electronic device to the local terminal is transmitted from the
portable electronic device in response to the first signal. For
example, the RFID tag 119 transmits a response signal back to the
RFID reader/writer 255. According to some embodiments of the
present invention, transmitting the second signal is performed
using power from a wireless excitation signal received from the
local terminal, such as an electrical induction signal from the
RFID reader/writer 255.
At step 615, positioning method priority information, which is
based on a location of the local terminal and is received from the
local terminal in response to the second signal, is processed. For
example, such processing can comprise reading the positioning
method priority information from a radio frequency identification
tag in the portable electronic device, such as where the RFID tag
119 receives positioning method priority information from the RFID
reader/writer 255 that is based on the location of the RFID
reader/writer 255 in a subway, train station, bus station, public
building, or vehicle, and the information is then read by the PMS
module 260. Further, the positioning method priority information
can comprise a current position of the portable electronic device,
such as specific latitude and longitude coordinates. That can
further reduce the need for a portable electronic device to employ
one or more of its available positioning methods.
At step 620, a positioning method priority list based on the
positioning method priority information is updated. For example,
according to the method 300 the PMPL 265 is updated.
At step 625, the position of the portable electronic device is
determined using a positioning method identified in the positioning
method priority list. For example, the position of the mobile
telephone 100 is determined using a positioning method that employs
the WLAN transceiver 220 based on a WLAN priority identified in the
PMPL 265.
Although various embodiments of the present invention have been
described in relation to the mobile telephone 100, those skilled in
the art will appreciate that embodiments of the present invention
can be included in various other types of portable electronic
devices, such as notebook computers, personal digital assistants
(PDAs), handheld radios, vehicle location systems, and various
other electronic appliances that may employ location services
(LCS).
Advantages of the present invention thus include enabling a
portable electronic device to determine an appropriate positioning
method in a particular circumstance or location without needing to
execute and test various available positioning methods. The
portable electronic device is thus able to conserve battery and
processor resources of the device, and conserve bandwidth resources
of a network to which the device is connected.
It will be appreciated that embodiments of the invention described
herein may be comprised of one or more conventional processors and
unique stored program instructions that control the one or more
processors to implement, in conjunction with certain non-processor
circuits, some, most, or all of the functions of determining a
position of a portable electronic device as described herein. The
non-processor circuits may include, but are not limited to, a radio
receiver, a radio transmitter, signal drivers, clock circuits,
power source circuits, and user input devices. As such, these
functions may be interpreted as steps of a method for determining a
position of a portable electronic device. Alternatively, some or
all functions could be implemented by a state machine that has no
stored program instructions, or in one or more application specific
integrated circuits (ASICs), in which each function or some
combinations of certain of the functions are implemented as custom
logic. Of course, a combination of the two approaches could be
used. Thus, methods and means for these functions have been
described herein. Further, it is expected that one of ordinary
skill, notwithstanding possibly significant effort and many design
choices motivated by, for example, available time, current
technology, and economic considerations, when guided by the
concepts and principles disclosed herein will be readily capable of
generating such software instructions and programs and ICs with
minimal experimentation.
In the foregoing specification, specific embodiments of the present
invention have been described. However, one of ordinary skill in
the art appreciates that various modifications and changes can be
made without departing from the scope of the present invention as
set forth in the claims below. Accordingly, the specification and
figures are to be regarded in an illustrative rather than a
restrictive sense, and all such modifications are intended to be
included within the scope of the present invention. The benefits,
advantages, solutions to problems, and any elements that may cause
any benefit, advantage, or solution to occur or become more
pronounced are not to be construed as critical, required, or
essential features or elements of any or all of the claims. The
invention is defined solely by the appended claims including any
amendments made during the pendency of this application and all
equivalents of those claims.
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